Field of the Invention
The present invention relates to a technology of controlling a so-called follow shot assisting function in an optical system.
Description of the Related Art
A follow shot is a capturing technique to express a sense of speed of a moving object through a flowing background, where a user pans an image pickup apparatus (referred to as a “camera” hereinafter) in synchronization with a movement of an object so that the moving object can stand still in the captured image. In addition, there is known a camera having a follow shot assisting function that provides a good follow shot even when a panning velocity changes by detecting a motion (vector) of an object in a captured image, and by shifting a shift lens in an image pickup optical system relative to the optical axis so as to reduce the movement of the object.
Japanese Patent Laid-Open No. (“JP”) 2006-317848 discloses a follow shot assisting method for calculating a lens shift amount necessary to position an object at a center in an image based on a detection result of vibrations of a camera using a vibration detector and a motion vector of the object in a captured image, and to shift the shift lens relative to the optical axis by the shift amount. The motion vector of the object is detected in a predetermined object area.
However, as disclosed in JP 2006-317848, the method for shifting the shift lens using the motion vector detected based on the captured image has the following disadvantages. When there are pluralities of object images in the captured image and each motion vector is detected, the shift lens may be controlled according to the motion vector of an object different from the main object to be captured or to be stopped by the user. Then, the main object is not made stationary in the captured image or is deviates from the captured image.